Product sorting apparatus for variable and irregularly shaped products

ABSTRACT

A wide variety of product types, sizes and shapes are sorted into designated destination bins or other outputs utilizing a computer controlled transport path that includes an infeed section and a pinch roller diverting section. The infeed section receives a singulated stream of products to be sorted, optically scans each product for a destination code and transports the products downstream to the diverting section. The diverting section consists of a series of individually and selectively controlled roller pairs in combination with a number of diverting gates. Each roller pair includes an upper foam covered pinch roller and a lower friction drive roller oriented such that products moving downstream pass between each roller pair until diverted from the transport path. An array of photoelectric detectors provide product position information to identify and track product movement through the apparatus. The computer controls the transport path by energizing individual drive rollers to effectuate downstream product movement, and actuating diverting gates to divert the products from the transport path into designated output bins according to their scanned destination codes.

This application is a continuation of application Ser. No. 07/982,718,filed Nov. 27, 1992 now abandoned, which is a continuation ofapplication Ser. No. 643,853, filed Jan. 22, 1991, now U.S. Pat. No.5,186,336.

TECHNICAL FIELD

This invention relates to separating and sorting packages, and moreparticularly to an apparatus utilizing a computer controlled transportpath to sort a wide variety of products into designated output bins.

BACKGROUND OF THE INVENTION

Historically, bulk products have been hand separated and sorted by humanoperators who manually separated the products into individual bins ordelivered the product to a sorting machine after inputting a productdestination code. The sorting machine then delivered the product to itsproper destination point according to the input destination code.Provision has also been made for the machine to scan the product for itsdestination code rather than have it manually input.

One drawback experienced with the manual method for separating andsorting is that total product processing time is a function of eachhuman operator's familiarity with the product and its post-separationand sorting destination. An operator who is unfamiliar with a particularproduct's destination or who is confronted with an unrecognized productwould be forced to check the product destination list to insure properproduct sorting. Operator unfamiliarity destination with the properproduct delays the sorting process, reduces net product throughput andcuts into the profits of the sorting operation. An additional drawbackof the manual separation and sorting process is its susceptibility toerror as a careless human operator may fail to correctly separate andsort the product into its intended destination bin.

Automated sorting machines have heretofore processed products through atransport path by sandwiching the product between two vertical conveyorbelts or by pushing the product on edge through a transport channel.Products are then diverted from the transport path into designated binsby inserting a diverting gate between the conveyors, or by pushing theproduct out of the transport channel. For each type of sorting machine,the transitional throughput for the drive mechanisms causing downstreamproduct movement are fixed. Thus, there was no ability to intermittentlyor individually control the downstream progress of each product. Inaddition, the distance between the two conveyor belts and the width ofthe processing channel are fixed for each machine. Thus, a furtherdrawback of these prior art sorting machines is the limitation of onlyprocessing products of one or a limited number of sizes as determined bythe spacing between the vertical conveyor belts or the channel width.Furthermore, the rigid shape of the belts and channel did not allow forirregularly shaped products to be processed. All nonconforming productswere therefore inconveniently separated or sorted by hand or by anothermachine.

The drawbacks associated with hand or prior art machine sorting reflectpoorly on the sorting operation both economically and in terms ofcustomer goodwill. Accordingly, there is a need for an automatedseparation and sorting apparatus that will efficiently and accuratelyseparate and sort into designated destination bins a wide variety ofproduct types, sizes and shapes.

SUMMARY OF THE INVENTION

The present invention overcomes the foregoing problems associated withmanual or machine sorting by providing an apparatus for sorting a widevariety of product types, sizes and shapes into designated receptacles.In accordance with the broader aspects of the invention, a computercontrolled transport path characterized by an infeed conveyor belt and apinch roller diverting sorter, receives a singulated stream of productsat the upstream input end, scans each product in the product stream fora destination identification label, and diverts the identified productfrom the transport path into a designated destination bin or takeawaybelt at the downstream output end according to the scanned destinationidentification label.

The infeed conveyor belt receives at its upstream end a singulatedstream of products to be sorted and transports the products downstreamto the diverting sorter. A bar code scanner located above the transportpath reads an identifying bar code on each product and transmits thecode identifier to a control computer. The computer compares thetransmitted identification code to a list of reference codes stored inthe computer's memory, determines the destination bin into which eachproduct in the product stream should be diverted, and stores productsequence and destination bin data in a list table to be referenced bythe computer during the sorting operation.

The diverting sorter includes of a series of roller pairs to effectuatedownstream product movement through the transport path and a number ofdiverting gates to divert products from the transport path intodesignated destination bins. Each roller pair comprises of anindividually and selectively computer controlled variable speed driveroller and a vertically adjacent non-driven pinch roller. The rollerpairs extend laterally across the width of the transport path and arepositioned relative to the transport path such that the plane definingthe transport path passes between the drive and pinch rollers. Thus,products traveling downstream through the diverting sorter transportpath pass between the roller pairs until diverted into a destinationoutput bin by one of the included diverting gates.

Orientation of the transport path and roller pairs in this mannerenables the drive roller to more efficiently cause downstream productmovement as the pinch roller acts to increase the friction force betweenthe product and the drive roller. Because the pinch roller is covered ina soft foam material, the apparatus can handle and sort irregularlycontoured products. Furthermore, use of a soft covered pinch rolleddecreases the likelihood that the pinching action will cause damage tofragile or delicate products.

The diverting sorter further comprises a number of computer controlleddiverting gates that are selectively placed between adjacent pinchroller pairs along the length of the transport path. A destination bincorresponding to each included diverting gate is positioned underneaththe transport path to receive diverted products. Actuation of adiverting gate by the computer directs a product from the transport pathinto the underlying destination bin according to the scannedidentification-bar code.

The control computer utilizes an array of sensors positioned along thetransport path to track product location within and movement through theapparatus. The tracked product information is continuously updated andcross-referenced to the product sequence and destination bin table toinsure that the proper diverting gates are actuated to accurately sortthe product stream. The use of individually and selectively controlledvariable speed drive rollers enables the computer, in response todetected product location information, to adjust the downstream velocityof products and control the relative position between products movingthrough the transport path. Computer roller control of individualproducts in this manner prevents tailgating of preceding productsthereby reducing the likelihood of product jams, stacking or inaccuratesorting.

The automated product separation and sorting apparatus of this inventionefficiently and accurately separates and sorts various sized and shapedpackages having attached identifying bar codes into designateddestination bins.

Possible applications include the sorting of magazines, postal mail andwarehouse inventory. Other advantages and applications deriving from theuse of the invention will readily suggest themselves to those skilled inthe art from consideration of the following Detailed Description takenin conjunction with the accompanying Drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention may be had by referenceto the following Detailed Description when taken in conjunction with theaccompanying Drawings, wherein:

FIG. 1 shows a perspective view of the product sorting apparatus inwhich parts have been cut away to more clearly illustrate certainfeatures of the invention;

FIG. 2 is a side view of the product sorting apparatus as shown in FIG.1;

FIG. 3 is a blowup side view of the diverting gate area in FIG. 2;

FIG. 4A and 4B are a longitudinal cross-sectional view of the productsorting apparatus as shown in FIG. 1;

FIG. 5 is a cross-sectional view of one roller pair for the productsorting apparatus as taken along line 5--5 in FIG. 2;

FIG. 6 shows a schematic diagram of the product sorting apparatus; and

FIGS. 7A, 7B and 7C shows a flowchart illustrating one embodiment forcontrolling the roller pairs and diverting gates to effectuate productsorting and downstream product movement.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, and particularly to FIG. 1, there isshown an apparatus 10 for sorting a wide variety of products. Theapparatus 10 defines a transport path, illustrated in part by arrows 12and 14, comprising an infeed conveyor belt 16 and a pinch rollerdiverting sorter 18. A number of destination output bins 20, locatedunder the diverting sorter 18, receive products selectively divertedfrom the transport path. Two representative destination output bins,labeled 20(1) and 20(2) are shown in FIG. 1. It will be understood,however, that the output bins 20 may be replaced by takeaway belts orother conveying mechanism to receive diverted products and transport forfurther processing. The apparatus 10 further includes a bar code scanner22 and a central processing unit 24. The main operating components ofthe apparatus 10 are supported over the output bins 20 by a frame 26.

In the operation of the apparatus 10, a singulated stream of individualproducts of various types, sizes and shapes to be sorted is receivedonto the infeed conveyor belt 16 and directed to the diverting sorter18. The stream of products may be hand placed on the apparatus 10 in asingle-file manner, or may be automatically singulated from a stack ofproducts by an apparatus similar to that described in commonly assigned,co-pending application for Letters Patent, Ser. No. 593,783 filed Oct.5, 1990. Computer control regulates entrance to, and controls downstreamproduct movement through the diverting sorter 18.

A tracking photoelectric cell 21, located at the upstream edge of theinfeed conveyor belt 16, detects the entrance of each product in theproduct stream into the apparatus 10. As the leading edge of the productblocks the photoelectric cell 21, the tracking algorithm executed by thecentral processing unit 24 calculates the time required for the productto pass and unblock the cell. This time is stored by the computer as theproduct length.

As the singulated product stream travels further along the infeedconveyor 16, bar code scanner 22 scans for an identification bar codelabel affixed to each product. The scanned bar code is transmitted tothe central processing unit 24 for comparison to a stored sort-and-tallybar code list that identifies the destination output bin 20 into whicheach scanned and identified product is to be sorted. It will beunderstood that bar code scanner 22 may be replaced by an opticalcharacter reader or other scanning apparatus that detect informationalparameters from each product. The detected informational parameters arethen used to determine the proper destination output bin 20 into whichthe scanned product is to be sorted. In the alternative, the destinationinformational parameters may be manually keyed in as the products enterthe apparatus 10.

The sequence of products detected by photoelectric cell 21 and theassociated product destination bar codes identified by scanner 22 arelinked by the processor to generate a product sequence and destinationbin table. This list of products and destination bins is stored by thecomputer to assist in product tracking and accurate sorting. When theproducts enter the diverting sorter 18, the central processing unit 24accesses the stored product table, tracks the progress of each productand transmits control signals to divert each product in the productstream from the transport path into its computer designated output bin20. As the products pass through the diverting sorter, their length mayagain be measured and compared to the product length data detected bycell 21 and stored in the product sequence table to identify thepresence of any unexpected or stray products.

The diverting sorter 18 consists of a series of roller pairs 34 arrangedon a horizontal plane. The central processing unit 24, through sensingmeans to be described, tracks the location and movement of products 30through the diverting sorter 18 by referencing the stored productsequence and destination bin table. In response to signals generated bythe central processing unit 24, individual roller pairs 34 areselectively energized to effectuate downstream product movement whilemaintaining a proper distance between consecutive products.

The diverting sorter further comprises a number of diverting gates 40that are selectively positioned along the diverting sorter 18 betweenadjacent roller pairs 34. As the tracked products move downstreamthrough the diverting sorter 18, the computer, referencing the productsequence and destination bin table, selectively opens and closesindividual diverting gates to direct the tracked products into theoutput bin 20 designated by the attached scanned bar code label andstored in the destination bin table. If the scanner 22 fails to find abar code label on the product or if the bar code detected by the scannerdoes not match an entry on the stored code list, the central processingunit 24 directs the diverting sorter 18 to transport the product into aresidual (reject) bin where the product is collected and either handsorted or returned to the infeed conveyor 16 to be reprocessed by theapparatus 10.

The central processing unit 24 preferably comprises a computer fordirecting all of the functions of the separating and sorting apparatus10 in accordance with a tracking and flow control software program to bedescribed. In the preferred embodiment of the invention, theaforementioned computer includes such features as an 80286 CPU, 640Kram, 1.2 MB floppy disk, 20 MB hard disk, two serial ports and oneparallel port. The computer, through the included Serial and parallelports, performs data acquisition functions, either by means of the barcode scanner 22 or by means of a sensor array to be described, andexercises individual and selective control over the elements of theapparatus 10, either by energizing the motors powering the infeedconveyor belt 16 and roller pairs 34 or by energizing the solenoids usedto actuate the diverting gates 40. As computers of this type are wellknown and the detailed construction of the computer itself does not forma part of the present invention, further description of the computer isdeemed unnecessary.

Sort-and-tally software for each anticipated product to be sorted arestored in ASCII data files located either on floppy disks or downloadedinto the computer hard disk. The sort-and-tally software storesrecognized bar codes and the location of the designated destinationoutput bin into which products labeled a stored bar code are to besorted. Several thousand valid bar codes may be input into the computerfor any given sort-and-tally software. At the end of each run, thecomputer generates a report that tallies occurrences of each detectedbar code. The report also tallies occurrences of unrecognized or missingbar codes to indicate the total number of products that were divertedinto the reject bin for reprocessing.

Referring now simultaneously to FIGS. 1, 2, 3, 4A, 4B, and 5, thediverting sorter 18 includes a plurality of roller pairs 34 anddiverting gates 40 arranged on a horizontal plane. The roller pairs 34and diverting gates 40 are rotatably mounted to an opposed pair oflongitudinally extending side plates, 42 and 44, in a manner to bedescribed. Each roller pair 34 is comprised of an individually andselectively controlled drive roller 36 and a vertically adjacent,non-driven pinch roller 38. The roller pairs 34 extend transverselybetween, and perpendicular to the opposed side plates, 42 and 44, andare positioned relative to each other such that the outer surface 46 ofdrive roller 36 and the outer surface 48 of the adjacent pinch roller 38tangentially meet at pinch point 50. Thus, rotation of drive roller 36causes pinch roller 38 to rotate in the opposite direction.

The product transport path, illustrated in part by arrows 12 and 14 inFIG. 1, passes between the series of roller pairs 34 and is interruptedonly when a diverting gate 40 opens to divert a product 30 into adestination output bin 20. The surface plane of the product transportpath is defined by the upwardly disposed surfaces of each diverting gate40 and each low-friction slider plate 28. The output transport path foreach diverting gate 40, illustrated in part by arrow 13, is defined by alow-friction output slide 29 leading from each diverting gate 40 to anassociated output bin 20.

The drive roller 36 is comprised of a shaft 52 having opposed ends, 54and 56, and a hard, high-friction cover 58 defining the outer surface 48of the roller. The drive mechanism for each drive roller 36 ispreferably a variable speed D.C. electric motor 60. A pulley 62 mountedto the motor 60 directs operating power from the motor to a secondpulley 64 by means of a drive belt 66. The second pulley 64 is attachedto end 54 of shaft 52 supporting drive roller 36. Thus, in the preferredembodiment, a single variable speed motor is utilized to actuate apulley 62 which in turn operates, through belt 66 and pulley 64, onedrive roller 36.

Each drive roller 36 is rotatably mounted to the diverting sorter 18 bymeans of a pair of openings, 68 and 70, drilled in the opposed sideplates, 42 and 44 respectively. A suitable low-friction bearing 72inserted in each opening 68 and 70 for rotatably supporting each shaftend, 54 and 56, of drive roller 36 to the side plates, 42 and 44respectively.

Use of a variable speed motor 60 for each drive roller 36 enables theupstream drive roller, upon opening of diverting gate 40, to beaccelerated thereby propelling product 30 positioned at the pinch point50 the output slide 29. Acceleration of the sorted product in thismanner results in a more uniform diverted product stack in the outputbin 20, thus facilitating any further product processing. In addition,upon opening of diverting gate 40, product acceleration diverts productsfrom the transport path more quickly, thereby increasing productthroughput processing and decreasing the likelihood of product jamscaused by premature closing of the gate.

Each pinch roller 38 is comprised of a shaft 74 having opposed ends, 76and 78, and a soft foam cover 80 defining the outer surface 48 of theroller. A soft foam cover 80 is utilized in the diverting sorter 18 tomore gently handle fragile or delicate products passing between theroller pairs 34. Furthermore, the surface of the soft foam coverconforms to irregular product surface contours and inhibits wandering orrotation of the product that may be caused by interaction between theirregular product surface and the pinch roller 38. This reduces thelikelihood of stacking or jamming of products during downstream movementthrough the diverting sorter 18.

Each pinch roller 38 is detachably mounted to the diverting sorter 18 bymeans of a pair of notches, 82 and 84, cut in the upper edge 86 of eachside plate, 42 and 44. Use of notches for mounting rather than openings(68 and 70), as used with drive roller 36, enables vertical movement ofthe pinch roller 38, as generally indicated at 88, as products 30 passbetween the roller pairs 34 during operation of the diverting sorter 18.

The ends, 76 and 78, of pinch roller 38, are restrained within notches82 and 84 by means of a pair of spring loaded retainers 90 mounted oneach side of the diverting sorter 18. Use of a retainer is not necessaryfor efficient operation of the apparatus 10 as the weight of each pinchroller 38 tends to naturally return the roller into the mounting notches82 and 84. The retainer 90, if used, is comprised of a clamp 92rotatably mounted to shaft end 76 and a leaf spring 94 mounted at oneend to clamp 92 and attached at the distal end to the side plate 42 ofthe sorter. The tension applied by leaf spring 94 is adjusted to insurethat pinch roller 38 applies continuous pressure on drive roller 36. Asuitable low-friction bearing may be inserted between shaft end 76 andclamp 92 to rotatably mount the pinch roller 38 to the retainer 90. Anidentical spring loaded retainer 90 is mounted to the opposite shaft end78 and side plate 44 to further assist in restraining pinch roller 38within notches 82 and 84.

The pinch roller 38 associated with each drive roller 36 appliespressure to the top side 98 of any product passing between roller pairs34 at the pinch point 50. The application of pressure to the product 30maximizes the friction force available between the product bottom side100 and the outer surface 46 of the drive roller 36. Maximization ofproduct/drive roller friction force assists in initiating and continuingdownstream product movement thereby increasing downstream productthroughput and decreasing the likelihood of product stacking or jamming.

A number of diverting gates 40, each having an associated destinationoutput bin 20, are mounted at selected locations in the diverting sorter18 such that two roller pairs 34 precede each gate. Each diverting gate40 consists of a rectangular surface 102 transversely extending between,and rotatably mounted to the opposed side plates 42 and 44 of thediverting sorter 18. A shaft 104, mounted to the downstream transverseedge 106 of the rectangular surface 102, rotatably supports thediverting gate 40 to the diverting sorter 18. The diverting gate 40 isopened and closed by rotating the rectangular surface 102 about itsattached shaft 104.

Rotational movement (opening and closing) of the diverting gate 40 iseffectuated by applying force to the upstream transverse edge 116 of therectangular surface 102. The drive mechanism for each diverting gate 40is preferably a rotary solenoid 118. A linkage 120, mounted between therotary solenoid 118 and the rectangular surface 102, applies the forcenecessary to open and close the diverting gate 40.

Linkage 120 is comprised of a rod 122 rotatably attached to an arm 126.Rod 122 is mounted at one end to the drive shaft 134 for the rotarysolenoid 118. The distal end of rod 122 is rotatably mounted at pivotpoint 124 to one end of arm 126. The other end of arm 126 is rotatablymounted, by means of a pin 130, to the longitudinal edge 128 ofrectangular surface 102 adjacent to diverting sorter side plate 42. Pin130 couples diverting gate 40 to linkage 120 through a channel 132 cutin side plate 42. Actuation of rotary solenoid 118 causes rod 122 torotate with the solenoid drive shaft 134. The distal end of rod 122applies the necessary force, through arm 126, to open and close thediverting gate 40.

The shaft 134 of the rotary solenoid 118 extends transversely across thewidth of the diverting sorter 18 to a corresponding second linkage 121mounted adjacent to side plate 44. The second linkage 121 is mounted toshaft 134 and longitudinal edge 136 in the same manner as linkage 120 ismounted to the shaft and edge 128. Application of actuating force toeach side of the rectangular surface 102 by linkage 120 and 121 asdescribed enables the diverting gate 40 to be more quickly opened andclosed, thereby increasing product throughput and decreasing thelikelihood of product jams. Furthermore, dual force actuation allows thediverting gate to be fabricated of light weight materials.

In the operation of the separating sorter 18, the motors 60 for eachdrive roller 36 and rotary solenoids 118 for each diverting gate 40 areselectively and individually energized by control signals output fromthe central processing unit 24 according to a tracking and flow controlprogram to be described. Product tracking (position and movement)information is detected by an array of photoelectric cells 138longitudinally dispersed over the separating sorter 18 and photoelectriccell 21 positioned above the infeed conveyor 18. Each photoelectric cellis mounted to a bracket 139 attached to the apparatus 10.

Tracking information from the photoelectric cells 138 is input into thecentral processing unit 24 and cross-referenced to the product sequenceand destination bin table compiled by the central processor from thescanned bar codes and tracking data collected by scanner 22 andphotoelectric cell 21. The tracking-and flow control program monitorsthe location of each product passing through the transport path,selectively articulates individual drive rollers 36 to cause furtherdownstream product movement while preventing tailgating of precedingproducts, and selectively actuates diverting gates 40 to direct productsinto their proper destination output bin 20 according to their scannedbar code 32. The photoelectric cells enable the apparatus 10 to measurethe length of each product passing between the roller pairs 36 in thesame manner as performed with photoelectric cell 21. This data iscompared to the product length calculation made by photoelectric cell 21and stored in the product sequence table to identify unexpected or strayproducts. All such identified products are added to the product sequencetable and passed through the diverting sorter 18 into a residual(reject) bin for reprocessing.

Each photoelectric cell 138 in the cell array is positioned on thediverting sorter 18 to detect the presence or absence of product at eachroller pair 34. The photoelectric cells 138 are positioned justdownstream of pinch point 50 to detect an infrared beam 140 directed at,and reflected by a retroreflector 142 located under each drive roller36. A channel 144, cut in the foam cover 80 of each pinch roller 38 asseen in FIG. 5, allows the photoelectric cell 138 to be advantageouslypositioned to detect product presence as soon as the products reach thepinch point 50.

Products passing between the elements of a roller pair 34 block theinfrared beam 140 from the retroreflector 142 at pinch point 50 creatinga "shadow" area on the separating sorter 18. The tracking and flowcontrol program executed by the central processing unit 24 scans theentire array of photoelectric cells 138 to detect all shadows on theseparating sorter 18, matches each shadow to a product on the productsequence and destination table and compares the tracked productinformation obtained to that stored from a previous scan. The trackingand flow control program thus continuously updates the storedinformation on the position, destination and relative movement of allproducts on the separating sorter 18.

Once the product destinations have been identified, the tracking andflow control program calls a subroutine to actuate stages of thetransport path in a manner to be described. Execution of the calledsubroutine selectively energizes individual roller pairs 34 to causedownstream product movement and prevent consecutive products fromtailgating. Furthermore, when each product reaches the diverting gate 40associated with the product's designated destination bin, the processor24 will divert the product from the transport path.

Referring now to FIG. 6, there is shown a schematic diagram of theproduct sorting apparatus 10. The apparatus 10 is comprised of threedifferent stages, the infeed stage 200, the diverting stage 202, and thereject stage 204. The infeed stage is comprised of the infeed conveyor18, photoelectric cell 21 and bar code scanner 22. Movement of theconveyor 18 causes the singulated stream of products 30 to break theinfrared beam of photoelectric cell 21 and be transported under the barcode scanner 22. The central processing unit 24 then assembles from thedetected information the product sequence and destination table used toaccurately track and sort the products.

Assembly of the apparatus 10 normally requires the use of a plurality ofdiverting stages 202. Three representative diverting stages, labeled202(1), 202(2) and 202(n), are shown in FIG. 6. Each diverting stage 202is identical and includes a diverting gate 40 preceded by two adjacentroller pairs 34. A photoelectric cell 138 is positioned at thedownstream edge of each roller pair 34 to detect the presence of aproduct 30 at the pinch point 50. A slider plate 28 and an outputdestination bin 20 complete the stage. The reject stage 204 includes anoutput bin 20 to collect all products 30 unsuccessfully sorted by thepreceding diverting stages 202.

Reference is now made simultaneously to FIGS. 6 and 7 wherein FIG. 7 isa flowchart for a subroutine called by the tracking and flow controlprogram executed by the central processing unit. The subroutine in FIG.7 operates to control downstream product flow through each divertingstage 202. For ease of discussion of the operating characteristics ofthe diverting stage flow control subroutine, each apparatus component inFIG. 6 has been labeled with a first numerical postscript denoting thediverting stage within which it is located and a second alphabeticalpostscript denoting the existence of multiple components within the samediverting stage.

For example, each diverting stage 202 contains two roller pairs 34. Thefirst roller pair in the first diverting stage 202(1) is thus labeled34(1a), and the second roller pair in the second diverting stage 202(2)is labeled 34(2b). The photoelectric cells 138 and pinch points 50 arethe only other multiple appearing elements within each diverting stage202, and have been labeled similarly. All other singularly appearingelements, for example, diverting gates 40 and output bins 20, contain asingle numerical postscript denoting the diverting stage within whichthe identified element is located. Thus, the diverting gate in the firstdiverting stage 202(1) is labeled 40(1) while the output bin in thesecond diverting stage 202(2) is labeled 20(2).

The subroutine for the tracking and flow control program is particularlydirected to: Scanning the pair of photoelectric cells, 138(na) and138(nb) within each diverting stage 202(n), articulating roller pairs34(na) and 34(nb) to effectuate control downstream product movement, andactuating each diverting gate 40(n) to sort products into designatedoutput bins 20(n) as determined by the bar code labels scanned prior toproduct entry onto the first diverting stage 202(1). In calling thesubroutine, the tracking and flowchart program first services the mostdownstream diverting stage 202(n) containing a product to be sorted. Theprogram then moves upstream addressing products in each consecutivediverting stage while continuing to monitor all previously servicedstages. The subroutine as shown in FIG. 7 is written to process only thefirst diverting stage 202(1) and reference hereinafter will be directedsolely to that application. It will be understood, however, that this isfor disclosure purposes only and that the actual subroutine called bythe tracking and flow control program is written to service any of the ndiverting stages 202(n) contained within the apparatus 10.

Upon entering the subroutine to service the first diverting stage202(1), operating step 300 causes the first roller pair 33(1a) to rotatein anticipation of the entrance of a product from infeed conveyor 18.Photoelectric cell 138(1a) is then scanned during inquiry step 302 todetermine if a product 30 has reached pinch point 50(1a). If photo cell138(1a) has not been blocked (i.e., no product is present at pinch point50(1a)), the subroutine continues to rotate roller pair 34(1a). If, onthe other hand, photo cell 138(1a) has been blocked, thus indicating thearrival of a product 30 at pinch point 50(1a), the subroutine, duringoperation step 304, sets and starts timer T(1).

The subroutine next searches during inquiry step 306 for producttracking and disposition information for the product present at pinchpoint 50(1a) from the product sequence and destination table storedwithin the central processor. The information is used to identify theproduct and its designated output destination bin 20(n) as determined bythe bar code label scanned during downstream movement through the infeedstage 200. If no such information is located, operational step 308 stopsrotation of roller pair 34(1a) and the subroutine pauses to await thetracking and disposition information. If timer T(1) should expire, asdetermined by inquiry sequence 310, prior to locating the necessarytracking and disposition information, the subroutine will stop allsystem rollers (step 312) and signal a system error (step 314).

If the product tracking and disposition information has been locatedduring inquiry step 306, a second timer T(2) is set and started byoperating step 316. Timer T(2) is a jam detection timer that willdetermine, through inquiry sequences 318 and 320, whether the secondroller pair 34(1b) in the first diverting stage 202(1) is clear toaccept the product presently located at the first pinch point 50(1a).Inquiry step 318 tests photoelectric cell 138(1b) for blockage at thesecond pinch point 50(1b), and if blocked, tests for expiration of jamdetection timer T(2) during inquiry sequence 320. If timer T(2) expiresprior to detection of an unblocked photoelectric cell 138(1b), a jamdetection error is declared by operational steps 322 and 324.

Failure to find photoelectric cell 138(1b) blocked activates both rollerpairs 34(1a) and 34(1b) to advance the product downstream duringoperational sequence 326. During advance cycle sequence 326, a secondjam timer T(3) is set and started (operational step 328) to test forproduct movement downstream to pinch point 50(1b). The subroutine thendetermines during "and" inquiry sequence 330 whether the upstreamphotoelectric cell 138(1a) is unblocked "and" the downstreamphotoelectric cell 138(1b) is blocked. Satisfaction of "and" inquirysequence 330 indicates that the product has fully advanced from pinchpoint 50(1a) to pinch point 50(1b). On the other hand, expiration of jamtimer T(3), as tested for in inquiry sequence 332, prior to satisfactionof "and" inquiry 330, signals the existence of a jam error (steps 334and 336).

If "and" inquiry 330 is satisfied, the subroutine brakes upstream rollerpair 34(1a) during operational sequence 338 and advances to decisionstep 340. At that point, the subroutine accesses the tracking andproduct destination information for the product now located at pinchpoint 50(1b) and determines if the product is destined for output bin20(1). Satisfaction of decision step 340 advances the subroutine throughstep 342 where the diverting gate actuation timer T(4) is set andstarted to synchronize the opening of diverting gate 40(1) with thearrival of the product to be sorted into output bin 20(1). Detection ofthe expiration of gate actuation timer T(4) during inquiry 344 advancesthe subroutine through operation step 346 to open the diverting gate40(1).

Roller pair 34(1b), never having been stopped since actuation in step326, then propels the product through open gate 40(1) into output bin20(1). Because the drive mechanism for each roller pair 36 comprises avariable speed motor, the subroutine may also be configured to directaccelerated rotation of roller pair 34(1b) thereby diverting productsinto each output bin 20(n) more quickly and uniformly. After opening thediverting gate 40(1), the subroutine sets and starts the diverting gatetimer T(5) during sequence 346-356 to hold gate 40(1) open for a timeperiod sufficient to allow the diverted product to clear the gate areaprior to gate closure by operating step 358. After the product has beensuccessfully diverted from the diverting stage 202(1), the subroutinereturns through step 374 to the tracking and flow control program.

If the product located at pinch point 50(1b) is not destined to bediverted into output bin 20(1), the subroutine attempts to advance theproduct to the next diverting stage 202(2) for further processing.Another jam timer T(6) is set and started by operation step 360. Thesubroutine then examines the upstream photoelectric cell 138(2a) in thesecond diverter stage 202(2). Detection, during inquiry step 362, of aproduct blocking photoelectric cell 138(2a) causes the subroutine tobrake roller pair 34(1b) and hold the product at pinch point 50(1b)until photoelectric cell 138(2a) is cleared. If the cell has not beencleared by the time jam timer T(6) expires, as tested for during inquirysequence 366, a jam detection error will be signaled. An unblockedphotoelectric cell 138(2a), on the other hand, allows the subroutine toadvance through operation step 372 thereby starting roller pair 34(1b),if not already actuated, and advancing the product to the next divertingstage 202(2). The subroutine then returns through step 374 to thetracking and flow control program to service another diverting stage202(n).

Although a preferred embodiment of the invention has been illustrated inthe accompanying Drawings and described in the foregoing DetailedDescription, it will be understood that the invention is not limited tothe embodiment disclosed, but is capable of numerous rearrangements andmodifications of parts and elements without departing from the scope ofthe invention.

We claim:
 1. Apparatus for sorting a stream of objects having varyingthicknesses comprising:transport means defining a transport path fortransporting a singulated stream of objects, said transport meansincluding a plurality of diverter gates; a plurality of drive rollersspaced apart along the transport means and between each one of theplurality of diverter gates; a plurality of pinch rollers, each one ofthe plurality of the pinch rollers mounted adjacent to one of theplurality of drive rollers for pinching an object against that driveroller; an object detector positioned upstream of each of said pluralityof drive rollers for detecting objects at the next downstream driveroller for generating an available signal for a downstream rolleravailable to receive an object; means for selectively actuating eachdrive roller independent of other of the plurality of rollers inresponse to the available signal to move an object along the transportpath toward the next adjacent roller; and a controller responsive to theavailable signal for tracking the position of objects in the singulatedstream and selectively actuating a drive roller independent of other ofthe plurality of drive rollers to propel an object downstream to thenext adjacent downstream drive roller only when the downstream roller isavailable to receive the object.
 2. The apparatus of claim 1 includingmeans for opening a diverter gate to divert a selected object from thesingulated stream, and wherein the controller independently actuates aselected drive roller and said means for opening to open a downstreamdiverter gate and to propel an object from the singulated stream throughthe opened diverter gate.
 3. The apparatus of claim 2 wherein thecontroller includes means for increasing the velocity of a selecteddrive roller to further accelerate the object through an openeddownstream diverter gate.
 4. The apparatus of claims 2 including meansto selectively move the plurality of diverter gates into the transportpath when opened and to cooperate with a respective one of the pluralityof drive rollers to deflect an object from the singulated stream.
 5. Theapparatus of claim 1 wherein each of said plurality of pinch rollersincludes a compressible material cover, the compressible material beingadapted for forcing each object in the singulated stream of objectsagainst the adjacent drive roller.
 6. Apparatus for transporting andsorting a singulated stream of objects comprising:transport meansdefining a transport path for transporting a singulated stream ofobjects; a plurality of diverter gates spaced apart along the transportpath, each diverter gate selectively and independently actuable andmounted to move into the singulated stream of objects for diverting aselected object from the singulated stream; a plurality of drive rollersspaced apart along the transport path, the plurality of drive rollersmounted between adjacent ones of the plurality of diverter gates; meansfor selectively actuating each drive roller independent of other of theplurality of rollers in response to an available signal to move anobject along the transport path toward the next adjacent roller; aplurality of pinch rollers, each one of the plurality of the pinchrollers mounted adjacent to one of the plurality of drive rollers; acompressible foam cover for each of said plurality of pinch rollers, thecompressible foam cover adapted to force an object against the adjacentdrive roller; and a controller responsive to the position of objectsalong the transport path for tracking the position of objects in thesingulated stream and selectively actuating each of the drive rollersindependent of other of the plurality of drive rollers only when thedownstream roller is available to receive the object to maintainseparation between objects.
 7. The apparatus of claim 6 wherein thecontroller includes means for independently actuating a selected driveroller and an adjacent downstream diverter gate to propel an objectthrough the actuated diverter gate.